The only SWAs --all of which are carried by infantry -- are light anti-tank guns, machine guns, and mortars. (Early-war and late-war versions.) They are all ordered as infantry. They are not ordered by the Artillery Bombard card.

The special artillery units -- Flak88, Long Tom (Big Gun), M7 Priest (Mobile Arty), and Nebelwerfer -- are all ordered by Arty Bombard. One caution: On that card, the Mobile Arty may move or battle twice, but may not do both.